A sunny pavement and the same kind of surface beneath a tree can feel very different, but “feels hotter” is only a starting observation. This investigation helps children compare locations systematically: same surface, same measuring method and readings taken close together in time. It also makes heat safety part of the method rather than an afterthought.
Choose the question carefully
Ask: “At this time, is the shaded section of this surface cooler than the sunny section?” That is narrower and more answerable than “Do trees cool cities?” A small family test can reveal a local pattern; it cannot represent every street, season or climate.
Materials
- A non-contact infrared thermometer, if available
- Clipboard, pencil and simple table
- Watch or timer
- Two or more matched surfaces, such as the same paving material in sun and shade
- Drinking water, hats and sun protection appropriate to your family
An adult should inspect the site first. Avoid roads, roofs, metal playground equipment, construction areas and any surface that may burn skin. Nobody needs to touch the ground. Stop if anyone feels dizzy, weak, nauseated, unusually tired or unwell, and move to a cooler place. Follow local heat guidance.
Plan a fair comparison
Pick points made from the same material and similar colour. One should have direct sun and one shade. Record cloud cover, time and whether either point is wet. Hold the thermometer at the distance recommended by its instructions and aim at a similar angle each time. Infrared tools vary, so use readings for comparison rather than assuming perfect accuracy.
Collect the readings
- Label the points A and B without writing on public property.
- Take three readings at A, waiting briefly between them.
- Move to B and repeat the same method.
- Calculate or identify the middle value for each set.
- Repeat later only if conditions remain safe.
Children aged 6–9 can circle the higher reading. Ages 10–12 can find the range and median. Teenagers can add a third material and explain why comparing asphalt with grass introduces two changing variables: shade and surface type.
Look beyond one number
Ask what else may affect the reading: passing cloud, moisture, wind, thermometer angle, surface colour or time since shade arrived. Tree shade can move. A wall’s shadow and a leafy canopy are not identical. Write these as limitations instead of treating them as mistakes.
Accessible roles
A participant who stays seated can operate the timer, record readings or direct where a partner measures. Use high-contrast labels and read numbers aloud. If heat sensitivity or a health condition makes outdoor work unsuitable, compare teacher-provided photographs and data indoors rather than pushing participation.
Connect the investigation
The pollinator container garden helps families observe plant needs across sun and shade. A rain gauge and weather log builds repeated measurement, and the mini BioBlitz shows how time and weather affect a short nature count.
State the conclusion honestly
Use the form: “At 2:15 p.m., the shaded paving in our test had a lower median surface temperature than the sunny paving.” Then add what you would need to investigate next—more days, more sites or a different surface. This keeps a useful result from becoming an oversized claim.
Help children reason about the evidence
Before measuring, ask each child to predict which surface will be warmer and why. Afterward, compare the readings with the prediction rather than treating a “wrong” guess as failure. Was the shaded surface made from the same material? Did a cloud pass? Was one reading taken closer to midday? These questions show why a fair comparison changes only one main condition at a time.
You can repeat the test later in the day or compare grass, soil and paving, but do not turn it into a contest to find the hottest object. Avoid metal playground equipment, parked vehicles and any surface that may burn. Adults should handle the thermometer if the instrument has a probe or requires close contact. The useful conclusion is local and modest: on this day, at this time, under these conditions, one measured surface was warmer than another.
